CN101839492A

CN101839492A - Method for recycling waste heat of silica fume

Info

Publication number: CN101839492A
Application number: CN201010188877A
Authority: CN
Inventors: 裴仲科; 路瑞玲; 陈奋义; 邵瑜; 李旭光; 张宏俊
Original assignee: LANXING SILICON MATERIALS CO Ltd
Current assignee: LANXING SILICON MATERIALS CO Ltd
Priority date: 2010-06-02
Filing date: 2010-06-02
Publication date: 2010-09-22
Anticipated expiration: 2030-06-02
Also published as: CN101839492B

Abstract

The invention relates to a method for recycling waste heat of silica fume in the production process of an industrial silicon furnace, which is characterized by adopting reverse-flow heat exchanging technology to collect the waste heat as efficient as possible on the premise of not changing a conventional flue. The method has the advantages of simple process flow, low input cost and capability of reducing heat discharge in the production process of industrial silicon, lowering surrounding heat radiation and improving production and operation environment. Moreover, the recycled heat is used for drying raw materials, so cost can be further saved and benefits are created for enterprises.

Description

A kind of method of SILICA FUME Waste Heat Recovery

Technical field

The invention belongs to metallurgical industry heat recovery technology field, particularly the method for SILICA FUME Waste Heat Recovery in the industrial silicon furnace production process.

Background technology

In the production process of industrial silicon, high melt can be discharged a large amount of flue gases, and its mean temperature is 550 ℃, and instantaneous temperature can reach 1000 ℃.Dust contained flue gas concentration 4g/Nm ³, SiO in the flue dust ₂Content reaches more than 85%, and therefore the dust of overflowing with flue gas is called silicon ash or SILICA FUME.This flue gas that contains SILICA FUME is taken away a large amount of heats, is about 33% of input energy, has also polluted environment when causing a large amount of thermal waste.

According to relevant document introduction, when producing the dried charcoal of industrial silicon consumption 350kg per ton, 60kg petroleum coke, 810kg coal, 1000kg wooden unit, the energy that electric furnace boiler face all gases and other substance combustions are emitted can reach 11600kWh.How reclaiming and utilize these energy, is an aspect containing very big potentiality in the industrial silicon production energy conservation.At present, there is high-temperature furnace gas in domestic industrial silicon manufacturer chimney directly to enter in the air by diffusing valve mostly, has not only caused enterprise's energy consumption higher relatively, and environment has also been polluted in the discharging of a large amount of high-temperature gases.

(Xu Shanwen, Zheng curse China to Chinese patent CN1991249A, the electric furnace smelting waste heat recovery with utilize process, 2007.7.4) technology of waste heat recovery of a kind of electric furnace high-temperature flue gas and utilization proposed, be high-temperature flue gas to be reclaimed enter waste heat boiler generation superheated steam, enter the steam turbine generating again, electric power system is produced for enterprise or is civilian, take all factors into consideration UTILIZATION OF VESIDUAL HEAT IN in addition, the hot flue gas that comes out with waste heat boiler is directly or behind storage heater, be used to smelt raw-material The pre-heat treatment, raw material enter in the smelting furnace after preheating again.Though that this technology can reach is energy-saving and cost-reducing, the effect of protection environment, has shortcomings such as technological process complexity, cost of investment height.

In addition, when producing, industrial silicon furnace needs a large amount of charcoals and wooden unit (consumption of raw materials of producing one ton of industrial silicon is charcoal 1.17t by norm, wooden unit 1.05t).Because of the charcoal quality of buying is uneven, moisture does not wait from 25%～50%.The charcoal water content can cause that greater than 30% and when unstable the carbon of electric furnace batching is unbalance, increases power consumption.Because water content exceeds standard, the initial stage that charcoal adds in the stove can make charcoal moisture content generation water gas reaction, and charge level temperature is increased simultaneously.Owing to the instability of charcoal moisture, not only increase the energy consumption of silicon stove, also be unfavorable for the operation of production technology and the operation of workman's operating environment.Solving the way that the charcoal water content exceeds standard at present, mainly is by artificial nature's airing, just must arrange the airing time according to weather condition, has not only increased the number of times of having bad luck of charcoal, the breakage that has strengthened charcoal, and the charcoal moisture disunity of natural drying.

Summary of the invention

The object of the present invention is to provide a kind of technological process is simple, construction cost is low industrial silicon produce in the recovery technology of SILICA FUME flue gas heat, solve problems such as the wasting of resources in the industrial silicon furnace production process and environmental pollution in the mode of economy.

Technical scheme of the present invention comprises the steps:

The mean temperature of coming out from industrial silicon furnace is that 450～550 ℃ high temperature SILICA FUME flue gas enters air cooler by petticoat pipe, the air cooler outer wall is provided with double pipe heat exchanger, the centrifugal high pressure air-introduced machine is that 20～40 ℃ thermal-arrest air is to flow in the opposite direction adverse current by in the double pipe heat exchanger with high-temperature flue gas with temperature, thermal-arrest air at this high temperature SILICA FUME flue gas and double pipe heat exchanger carries out heat exchange, heat in the high temperature SILICA FUME flue gas by the thermal-arrest absorption of air after temperature drop to 150～260 ℃, flue gas enters sack cleaner, thermal-arrest air behind the absorption heat enters hypomere UTILIZATION OF VESIDUAL HEAT IN technology, and the total amount of heat rate of recovery is 30%～60%.

Above-mentioned double pipe heat exchanger is to adopt diameter to be enclosed within the flue outside greater than the pipe of flue, and the hot flue gas in the flue of flowing through passes through the flue inner pipe wall with the one other fluid in the heat transferred heat exchanger.In described heat exchanger, adopt the countercurrent heat exchange mode to collect heat, here the preferred air of thermal-arrest fluid of Cai Yonging.Air is via in the centrifugal high pressure air-introduced machine lead-in bushing formula heat exchanger, flows to opposite with the interior high-temperature flue gas direction of flue.

As a kind of preferred version, the double pipe heat exchanger outer wall described in the said method is surrounded by insulation material, the preferred rock cotton board of described insulation material, block of glass wool.

Use the major advantage of above-mentioned double pipe heat exchanger to be: 1. simple in structure, easy construction, investment cost is low for factory; 2. heat conductive efficiency height.It is a kind of pure adverse current type heat exchanger, can also choose suitable sectional dimension simultaneously, to improve fluid velocity, increase the heat transfer coefficient of two side liquids, so its heat-transfer effect is good.

Above-mentioned flue-gas temperature when entering sack cleaner generally is controlled at 150～260 ℃, if the too high cloth bag that burns out easily of temperature, and life-span of reducing cloth bag, temperature is crossed and lowly can be made deashing and the transportation of silicon ash etc. cause difficulty.

The air quantity scope of described centrifugal high pressure air-introduced machine is at 824～123090m ³/ h, blast be at 3110～16250Pa, with the flow velocity of control thermal-arrest air at 4～10m/s.Air quantity preferable range 100,000～110,000 m ³/ h, the preferable range 10000～14000Pa of blast, the preferable range 6～10m/s of thermal-arrest air velocity.

As a kind of embodiment preferred, can under the effect of air-introduced machine, import the raw material drying operating room with the thermal-arrest air that reclaims heat by pipeline, utilize heat that raw materials such as charcoal are heated and dewater at this.

Beneficial effect of the present invention: compared with prior art, technological process of the present invention is simple, input cost is lower, under the prerequisite of not transforming existing flue, adopt the countercurrent heat exchange technology to collect waste heat as far as possible efficiently, the heat of collecting can be used for dry raw material, and the residue waste heat also can be as heating or other purposes.

By enforcement of the present invention, not only can reduce the industrial silicon discharging of heat in process of production, the heat radiation around reducing improves the production operation environment, and more can to save cost be enterprise's create beneficial result to the heat of the Hui Shouing drying that is used for raw material in addition.Therefore at China's industrial silicon production field, the present invention has great promotional value, and can lead China's industrial silicon industry to develop to economizing type, environmentally friendly direction.

Description of drawings

Accompanying drawing 1 is a process chart of the present invention.

1. industrial silicon furnace; 2. petticoat pipe; 3. flue; 4. air cooler; 5. double pipe heat exchanger; 6. air blast; 7. sack cleaner; 8. residual heat using device.

The specific embodiment

As shown in Figure 1, the mean temperature of being come out by industrial silicon furnace 1 is that 550 ℃ high temperature SILICA FUME flue gas enters flue 2 house stewards, enters the air cooler 4 that links to each other with flue 2, and the parameter of air cooler 4 is Φ 2820mm, δ 8mm, long 30 meters.Air cooler 4 outsides are with a double pipe heat exchanger 5, and double pipe heat exchanger 5 outer walls are surrounded by adiabator layer, and insulation material is an aluminium skin rock wool.Simultaneously, the thermal-arrest air enters air blast 6 by air blast 6 inlet valves, and pressure improves after air blast 6 outlet valves are pooled to the blower export house steward, delivers to double-tube heat exchanger 5.The flow of thermal-arrest air is at 12000Nm ³Air velocity 10m/s in the/h, control valve.

In double pipe heat exchanger 5, the thermal-arrest air carries out the capture of heat with respect to flue gas in the mode of overall countercurrent flow, absorbs the sensible heat of air cooler 4 outer walls, and temperature gets a promotion.In this process, the temperature of SILICA FUME flue gas is reduced to 230 ℃ by heat exchange by 550 ℃, send into sack cleaner 7 and be for further processing, and the thermal-arrest air themperature rises to 150 ℃ by room temperature, enter hypomere residual heat using device 8, reclaim 40% of the entrained heat of flue gas.The heat that reclaims is used for the drying of raw materials such as charcoal, needs dry 1.17 ten thousand tons of charcoals, be equivalent to save coal-fired 3 tons every day to produce 10000 tons of industrial silicons per year.

Claims

1. the method for a SILICA FUME Waste Heat Recovery is characterized in that, comprises the steps:

2. method according to claim 1 is characterized in that, described double pipe heat exchanger outer wall is surrounded by insulation material, and described insulation material is rock cotton board or block of glass wool.

3. method according to claim 1 is characterized in that, the air quantity of described centrifugal high pressure air-introduced machine is 100,000～110,000 m ³/ h, blast are 10000～14000Pa.

4. method according to claim 1, it is characterized in that, described UTILIZATION OF VESIDUAL HEAT IN technology is will reclaim the thermal-arrest air of heat by pipeline, imports the raw material drying operating room under the effect of air-introduced machine, utilizes heat that charcoal or wooden unit raw material are heated and dewaters at this.